Question

An automobile engine has an efficiency of 20% and produces 6000 J work. Find

the heat rejected by the engine. 

Answer 1

Given:

$W=6000\:\rm J$

$\eta=0.2$

The heat rejected by the engine

$$Q=\frac{W}{\eta}=\frac{6000\:\rm J}{0.2}=30\:000\:\rm J$$